1. Field of the Invention
The present invention relates to ionic substance removing material for use in a clean room such as a super-clean room. The invention relates, more particularly, to a covering material or member for covering a concrete wall of the clean room or a garment to be used in such super-clean room. The invention relates also to a method of manufacturing the material.
2. Description of the Related Art
As the concrete wall covering material or member for covering a concrete wall constituting e.g. an interior wall of a construction work, there have long been known such interior materials or members as a panel, board, sheet, paper material and so on. Also known is a concrete wall covering member with improved anti-dust generating property for use in particular in covering a concrete wall of a clean room.
In recent years, there has been demand from the semiconductor industries for higher integration of print wiring for example. It has been found out, however, that with prevention of dust generation in a clean room, improvement achievable in the degree of integration falls short of the industries' demand. For this reason, the industries have been considering the possibility of meeting the demand for higher integration by removing not only solid particles through prevention of dust generation inside the room, but also volatile, organic and inorganic chemical contaminants, Specifically, it has been proposed to remove the chemical contaminants by incorporating a chemical filter within a ventilation system of the clean room.
However, with the conventional method of removing chemical contaminants which relies solely on the incorporation of a chemical filter within the ventilation system of the clean room, ionic gases present in the clean room cannot be eliminated satisfactorily. Hence, the conventional method has been unable to achieve complete freedom from bacteria, dust and chemical contaminants.
Then, the present inventors have conducted extensive analysis on the above-described situation. The analysis has led the inventors to the following realization. Namely, a concrete wall used for constructing a clean room discharges therefrom various kinds of inorganic ionic substances into the clean room and these ionic substances cannot be removed by the chemical filter. Then, if the source of the ion gas generation is completely shielded, it will become possible to achieve improvement toward complete freedom from bacteria, dust and chemical contaminants. However, in the case of the conventional concrete wall covering material, attention has been paid solely on its dust generation preventing performance. For this reason, it has been impossible to remove the ionic gases present in the clean room.
In view of the above-described state of the art, a primary object of the present invention is to provide, in e.g. a clean room, greater freedom from bacteria, dust and chemical contaminants by preventing volatilizing discharge of ionic gases from the concrete wall surface.
A further object of the present invention is to provide a method capable of easily and reliably removing volatilized or floating ionic substances within a working atmosphere.